package com.itheima.api;

import java.util.ArrayList;

public class Inter {
    public static void main(String[] args) {
       Integer i1=100;
        System.out.println(i1);
        int i2=i1;
        System.out.println(i2);
        Integer i3=100;
        i3+=200;
        System.out.println(i3);
        Integer i4=null;
        if (i4!=null){
            i4+=200;
            System.out.println(i4);
        }
        ArrayList<Integer> list=new ArrayList<>();
        list.add(1);
        list.add(2);
        list.add(3);
        for (int i = 0; i < list.size(); i++) {
            int a=10;
            System.out.println(list.get(i));
        }
    }
}